NHTSA complaint #11739092

Owner complaint summary

I am submitting a complaint regarding premature exhaust system failure on my 2020 Buick Enclave involving the front exhaust pipe/exhaust manifold/catalytic converter assembly. The issue appears very similar to the conditions described in GM Special Coverage programs N212356540 and N242445280 involving exhaust pipe and bracket failures on related GM crossover platforms. The mounting brackets/support brackets on the front exhaust pipe appear to fail or separate, which places excessive stress on the flex section of the exhaust system. This movement and stress can cause the flex pipe/manifold area to crack and may ultimately damage the catalytic converter assembly itself. My vehicle developed: Exhaust leak Loud ticking/exhaust noise Rich/lean oxygen sensor fault conditions Exhaust fumes entering or potentially entering the cabin Passenger dizziness while riding in the vehicle Concern for carbon monoxide exposure The repair facility documented that the exhaust leak should be repaired as soon as possible because exhaust fumes may enter the vehicle cabin. The estimated repair cost is approximately $1,700 for replacement of the integrated catalytic converter/exhaust manifold assembly. This appears to be more than ordinary wear and tear. The failure pattern is consistent with bracket/support failure causing abnormal stress and cracking in the exhaust system upstream near emissions components. Because these failures can allow exhaust gases and possible carbon monoxide exposure into the passenger compartment, I believe this issue represents a significant safety concern and warrants investigation for 2020 Buick Enclave vehicles and related GM crossover platforms.